How horses (Equus caballus) see the world: humans as significant objects
Résumé
The aim of this study was to determine whether horses have a kind of memory of humans
(based on previous interactions), leading to a general significance of humans revealed by their
reactions to humans in subsequent interactions. This hypothesis was tested on 59 adult
animals (coming from 3 riding schools with similar life conditions) using three types of
behavioural tests, which involved an unknown experimenter and corresponded to three
potential memories of the relation (not work-related, using work-related objects, unfamiliar
working task). To get a broad overview of the horses’ reactions to humans, we recorded both
investigative and aggressive behaviours during the tests, representing respectively a “positive”
and a “negative” memory of the relationship. It appeared that while correlations between tests
revealed a general perception of humans as positive or negative, unusual tests, i.e. that are not
usually performed, elicited more positive reactions. Thus, some horses reacted positively to a
motionless person in their box, but negatively when this same person approached them, for
example with a halter. In overall, aggressive reactions to the experimenter were more reliable
indicators of the relationship than positive reactions. Altogether, the results support the
creation of a memory of humans by horses which impacts their reactions in subsequent
interactions.